Akai AT 2400 Service Manual

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AKAI STEREO TUNER

MODEL AT " 2400

SECTION 1 SERVICE MANUAL ............................. 2
SECTION 2 PARTS LIST .................................. 21
SECTION 3 SCHEMATIC DIAGRAM ......................... 31

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:52EF*

VIII.

SECTION 1

SERVICE MANUAL

TABLE OF CONTENTS

TECHNICAL DATA ............................................
DISMANTLING OF UNIT . .
CONTROLS ...................................................
PRINCIPAL PARTS LOCATIONS ..................................
OPERATING PRINCIPLES OF QUADRATURE DETECTION SYSTEM . . . .
OPERATING PRINCIPLES OF PLL CIRCUIT EMPLOYED IN

STEREO DEMODULATION CIRCUIT .....
1. PLL CIRCUIT OPERATION ....................................
2. STEREO DEMODULATION CIRCUIT ............................

. TUNER SECTION ADJUSTMENT ..................................

1. FM SECTION ADJUSTMENT ...................................
2. AM SECTION ADJUSTMENT ...................................
TUNING CORD THREADING . . . , ...............................
COMPOSITION OF P.C BOARDS .................................
1 FM IF P.C BOARD T2-5420A, LED P.C BOARD T2-54ZOB ...........
2. FRONT END PC BOARD T2-5421 ..............................
3. POWER SUPPLY P.C BOARD T2-5419 ...........................

8
8
8
10
ll
12
13
14
14

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I. TECHNICAL DATA

FM TUNER SECTION

FREQUENCY RANGE
SENSITIVITY (IHF)
CAPTURE RATIO
SELECTIVITY (IHF)
IMAGE REJECTION

IF REJECTION

SPURIOUS REJECTION
AM SUPPRESSION
SIGNAL TO NOISE RATIO

88 MHz to 108 MHz

1.8uV

1.0 dB

More than 80 dB

More than 90 dB (913 MHZ)
More than 100 dB (98 MHz)
More than 100 dB (98 MHz)
55 dB

75 dB

HARMONIC DISTORTION MONO Less than 0.2% (100% modulation)
STEREO Less than 03% (100% modulation)

TUNING INDICATOR Signal Strength meter and Center Tuning meter
MUTING Level Control (SuV to lDOuV)/SWIIChable to ON-OFF
STEREO SEPARATION More than 42 dB (1 kHz)
SUB CARRIER SUPPRESSION More than 65 dB
OUTPUT VOLTAGE VARIABLE From 0 mV to 1.6V

FIXED 0.77V (100% modulation)
ANTENNA INPUT IMPEDANCE 300 ohms balanced, 75 ohms unbalanced
AM TUNER SECTION
FREQUENCY RANGE 520 kHz to 1,605 kI-Iz
SENSITIVITY (IHF) 180uV/m (bar antenna), ISuV (external antenna)
SELECTIVITY (IHF) More than 30 dB
IMAGE REIECTION More than 55 (13 (1,000 kHz)
IF REJECTION More than 45 dB
SIGNAL T0 NOISE RATIO More than 50 dB
OUTPUT VOLTAGE VARIABIJZ From 0 mV to 550 mV

FIXED 250 mV (30% modulation)
ANTENNA Built-in {errite' bar antenna
MISCELLANEOUS
SEMICONDUCTORS Transistors: 12= Diodes: 9, FETs: 1, ICs: 4

POWER REQUIREMENTS

CSA, UL and LA models: 120V, 60 Hz
CEE models: 220V, 50 Hz

Other models: 110/220/240V, 50~60 Hz Switchable

DIMENSIONS 440(W) x 141(H) x 336(D) mm
(I73 x 516 x 13.2) inches
WEIGHT 6.6 kg (14.5 lbs)

For improvement purposes, specifications and design are subject to change without notice.